Project Summary/Abstract Congenital heart diseases (CHD) affect nearly 1% of children born in the United States (US), with many of them requiring heart surgery to avoid mortality or significant morbidity. Advances in the surgical management of CHDs have led to a growing population of CHD survivors, with now over 2 million persons with CHD in the United States, more than half of whom are adults. While survival to adulthood is now excellent for CHD patients, for many CHD types the mortality has simply shifted a few decades and now occurs in adulthood. Moreover, with age, these patients are continuously exposed to additional cardiovascular and non- cardiovascular morbidities along with the general population, and risk for these morbidities is likely higher as they are expected to create synergistic injury leading to additional premature mortality. Importantly, little is known concerning educational attainment, employment, and social relationships among this growing population. Understanding long-term outcomes is important for identifying opportunities for intervention and planning for health care services in this population with high resource utilization. Our project aims to fill important gaps related to the long-term outcomes for patients with CHD by linking the Pediatric Cardiac Care Consortium (PCCC), a large US-based registry for interventions of CHDs, with the National Death Index (NDI). This linkage allowed us to constitute a cohort that describes the long-term mortality of patients with an operated CHD. Since the PCCC registry is unparalleled in its size and scope, this approach provides the most powerful data source in the US to examine the trajectory of outcomes for patients operated for CHD now reaching adult age. However, besides mortality another important outcome for patients surviving various interventions for CHD is the development of end stage cardiac failure or pulmonary hypertension resulting in the need for organ transplantation. To address this limitation, we supplemented this dataset with linkage with the Organ Procurement and Transplantation Network (OPTN) research registry to obtain information regarding listing for transplant and organ transplants in the same cohort. In the next phase of our project, both death and transplant data will be updated through 2021 to assess characteristics related to survival and transplant within this aging cohort. In addition, as part of the continuation of our project we will survey patients and their siblings to determine the effects of the disease on the long-term medical, neurocognitive, and psychosocial outcomes for survivors of CHD compared to their siblings and the general population and to identify relevant prognostic factors that may be associated with those outcomes Completion of this study will provide a realistic and comprehensive view of expected outcomes after congenital heart surgery. This information will be useful to all relevant stake holders for the population of CHD and will promote engagement of patients and their families, care providers, health care administrators and public health officers to improve outcomes in this vulnerable population.